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Quantitative analysis of HBsAg, IgM anti-HBc and anti-HBc avidity in acute and chronic hepatitis B

2006; Elsevier BV; Volume: 37; Issue: 3 Linguagem: Inglês

10.1016/j.jcv.2006.06.011

1873-5967

Anna Rodella, Claudio Galli, Luigina Terlenghi, Francesca Perandin, Carlo Bonfanti, N. Manca,

Hepatitis Viruses Studies and Epidemiology

We evaluated hepatitis B virus (HBV) serological markers by novel, quantitative immunoassays in order to study their behaviours and possible role in the various phases of HBV infection.The quantitative determination of HBsAg and anti-HBc/IgM by chemiluminescent immunoassays (Abbott Architect) and the calculation of anti-HBc avidity index have been carried out on repository specimens from patients with acute or chronic hepatitis B.In acute hepatitis the levels of HBsAg were generally >10,000 UI/mL and decreased sharply in the recovery phase. In 35 anti-HBe-positive chronic hepatitis cases HBsAg levels were generally lower than 10,000 UI/mL (mean: 2655), whereas in five HBeAg-positive chronic hepatitis patients the mean value was 78,756 UI/mL and 90% of specimens exceeded 10,000 UI/mL. The lowest values (mean: 1029 IU/mL) were found in the seven patients with minimal hepatic damage. IgM anti-HBc antibodies were positive in all acute cases and in 68/207 samples (32.85%) from patients with chronic hepatitis, with significantly lower levels (average sample/cutoff (S/CO) ratio: 2.95 in chronic cases versus 25.96 in acute cases; p<0.005). A S/CO value of 10 for anti-HBc IgM had a 100% negative predictive value and a 99.13% positive predictive value for acute hepatitis B. The study of anti-HBc avidity by an experimental procedure showed that an avidity index (AI) threshold of 0.7 had a good efficacy to discriminate the cases of chronic hepatitis, among whom only 2 specimens out of 193 (1.04%) had an AI<0.7.The quantitative determination of HBsAg, anti-HBc/IgM and anti-HBc avidity provides additional information and may be useful in the differential diagnosis of acute and chronic HBV infections and in the follow-up of chronically infected patients.